Toph, Greatest Earthbender + Power Depot + Crystalline Crawler + Altar of Dementia + Benevolent Hydra

Toph, Greatest Earthbender

Power Depot

Crystalline Crawler

Altar of Dementia

Benevolent Hydra

How it works

1. Play Power Depot, which will enter with a +1/+1 counter on it due to its modular ability
2. Cast Toph either from your hand or from the command zone by paying 2 plus commander tax if applicable.
3. When Toph enters, it triggers, earthbending Power Depot and putting a number of +1/+1 counters on Power Depot equal to the mana spent to cast Toph, increased by Benevolent Hydra.
4. Activate Altar of Dementia by sacrificing Power Depot.
5. When Power Depot dies, its modular ability and Toph trigger.
6. Resolve the modular trigger, putting the +1/+1 counters that were on Power Depot onto Crystalline Crawler, increased by Benevolent Hydra.
7. Resolve the Toph trigger, returning Power Depot from your graveyard to the battlefield tapped. Power Depot will enter with a +1/+1 counter on it due to its modular ability
8. Resolve the Altar of Dementia ability.
9. Activate Altar of Dementia by sacrificing Toph. Choose to return Toph from your graveyard to the command zone.
10. Activate Crystalline Crawler by removing a +1/+1 counter from it, adding R/G.
11. Repeat step 10 until you have enough mana to cast Toph.
12. Repeat from step 2.